This invention relates to vehicular and pedestrian traffic flow and traffic light controls. In particular, the present invention relates to a method and system for increasing the flow of vehicular traffic on city streets and avenues while minimizing idling time and intermodal conflicts. Intermodal conflicts, as used herein, refers to slowing of vehicle traffic flow due to the potential for an accident or injury, involving either two or more vehicular streams of traffic, or, a vehicle and a pedestrian stream of traffic at street intersections. Intermodal conflicts are, of course, life threatening and in addition, they increase travel time while disrupting smooth traffic flow. The present invention is particularly suitable for being superimposed on existing grid-like systems of crossing roads or streets and avenues, as, for example, those that currently exist on the island of Manhattan, within New York City. A grid-like system as used herein, refers to a road network having primarily parallel roads (preferably with wide pavement, like avenues) with intersecting cross streets or roads, as in the case of Manhattan, cross-streets (less wide pavement) at right angles to the avenues.
The present invention relates to a method and system for controlling the traffic signals (red and green lights) on the avenues and streets in such a manner that idling time is minimized while vehicular traffic flow is maximized, all with reduced intermodal conflicts. The present invention is intended for and preferably used along with my Road Traffic Network, referred to herein as the Multiple Loop System, described in and illustrated by my already issued U.S. Pat. No. 4,927,288 issued May. 22, 1990. The teachings of my Road Traffic Network or Multiple Loop System (hereinafter the "MLS") are incorporated herein by reference. In addition, my other already issued patent, U.S. Pat. No. 5,092,705 issued Mar. 3, 1992, relating to a method and system for controlling vehicular and pedestrian traffic at intersections of the MLS is also incorporated herein by reference. U.S. Pat. No. 5,092,705 describes a vehicular and pedestrian traffic pattern flow system. In brief summary, that patent relates to a method for controlling the vehicular traffic light signals at intersections of avenues and cross streets, along with "Walk No Walk" traffic signals for pedestrians at the cross walks, so that the MLS system operates to its maximum efficiency, all while preserving safety and reducing intermodal conflicts.
The present invention relates to a method and system for simultaneously controlling traffic signals at a plurality of intersections on a grid network. The duration of the timed phases of the vehicular traffic light signals is set according to a formula based on safe yet anticipated travel speeds. The invention also relates to a system for coordinating the traffic signals for adjacent avenues and intersecting cross streets of the MLS system. Preferably, the present invention is coordinated with both the MLS System and the method of controlling vehicles and pedestrians (the '705 patent) so that travel and idling time for vehicles is minimized while maximizing traffic flow. This is of course environmentally desirable and, in addition, will reduce vehicle operators' frustration as a consequence of traffic congestion and allow more vehicles to travel on the same road network in less time, without gridlock. It should reduce traffic problems and the attendant negatives associated therewith. The present invention accomplishes these goals while preserving safety and reducing intermodal conflict.